Basically, the processing of photographic materials comprises a color development process and a desilvering process. The desilvering process comprises a bleaching process and a fixing process or a bleaching and fixing process. The processing of photographic materials also comprises additional processes such as rinsing and stabilization.
In the color development, exposed silver halide is reduced into silver, and at the same time an oxidized aromatic primary amine developing agent reacts with a coupler to form a dye. During this stage, halogen ions generated by a reduction field of silver halide dissolve and accumulate in the developing solution. Also, constituents such as a development restrainer contained in the silver halide photographic material dissolve and accumulate in the color developing solution. In the desilvering process, silver generated by development is bleached by an oxidizing agent, and then all silver salts are removed by the fixing agent as soluble silver salts from the photographic material. There has heretofore been known also the combined bleach-fixing method in which bleaching and fixing are carried out simultaneously in one bath.
As described above, in the color developing solution, the development restrainer accumulates by the development processing of the photographic material. On the other hand, the color developing agent and benzyl alcohol are consumed, or accumulated in the photographic material and removed from the color developing solution. Thus the concentrations of these constituents decrease. Therefore, in the development processing method wherein large amounts of silver halide photographic materials are continuously processed in an automatic developing machine or the like, it is necessary to provide a means for maintaining the concentrations of constituents of the color developing solution within a predetermined range for eliminating changes in development finish characteristics caused by changes in concentrations of the constituents. Normally, as such means, a method wherein a replenishing solution for replenishing the insufficient constituents and diluting the unnecessary increasing constituents is added is used. However, this method has the economical and pollution drawbacks since a large amount of overflow which must be discarded arises when the replenishing solution is added. Accordingly, in recent years, in order to decrease the amount of overflow, it has been proposed to use a developing solution regeneration method using an ion exchange resin or electrodialysis, a method of adding small amounts of concentrated replenishing solution, or a method wherein a regeneration agent is added to the overflow solution for using the overflow solution as the replenishing solution.
Regeneration of the developing solution is carried out by removing bromide which is an unnecessary accumulated constituent and replenishing the insufficient constituents. However, these methods, i.e. the method using an ion exchange resin and the method using electrodialysis, have the drawback that the development processing characteristics for the photographic material are adversely affected unless the constituents of the developing solution are quantitatively determined by chemical analysis and their quantities are made constant. Thus these methods require complicated control, and therefore it is almost impossible for small-scale development stations or mini labs. having no particularly skill to introduce the methods. Further, with these methods, the initial cost is very high.
Further, with the method in which a regenerating agent is added to the overflow solution for using it as a replenishing solution, no particular skill is required. However, with this method, spaces for a stock tank or the like are necessary. Also, the method is troublesome for the development stations. Therefore, it is difficult for the mini labs. or the like to introduce the method. On the other hand, the method of low replenishment with concentrated replenishing solution does not require a new apparatus and is easy to conduct processing control. Therefore, this method would be suitable for small-scale laboratories such as so-called mini lab. However, this method has some drawbacks. For example, when a p-phenylenediamine derivative is used as the color developing agent in a developing solution which is alkaline, particularly, which has a pH value of 9 or higher, an amine base or free amine readily deposits in the replenisher tank or pipes (particularly where soft polyvinyl chloride hoses are used) at cold districts or under cold weather. Also, as color printing propagates in recent years, the color development processing is carried out at various districts in the world. For example, in laboratories at hot or dry districts such as tropics or deserts, crystals arise at the boundary between the tank and the replenishing solution due to evaporation from the replenisher tank.
As the technique for increasing the solubility of the p-phenylenediamine derivative in the developing solution and thereby eliminating the aforesaid drawback, there have heretofore been known to add alkylbenzenesulfonic acid as described in British Pat. No. 669,505, to add methyl cellulose as described in Japanese Patent Publication No. 46-41676, to add lactose or hydroxypropyl cellulose as disclosed in Japanese Patent Publication No. 50-21250, and to add a carboxylic acid derivative or a quaternary ammonium compound having hydroxyalkyl group as disclosed in Japanese Unexamined Patent Publication Nos. 53-70436 and 53-69035.
However, these techniques of adding the above-mentioned compounds to the developing solution have various drawbacks and are not satisfactory in practice. Specifically, alkylbenzenesulfonic acid must be added in a large amount on the order of 100 to 200 g/l. Cellulose can improve the solubility of p-phenylenediamine derivative in the developing solution with the addition of a relatively small amount. However, for example, methyl cellulose or the like decreases the solubility when it is added in an amount larger than a predetermined amount to the developing solution. Further, when the processing solution is provided as a kit, since the solubility of the additive is markedly low, long time and particular devices are necessary for production of the processing agent kit. Also, the effect of the carboxylic acid and quaternary ammonium compound on prevention of crystal deposition at the evaporation surface is small. Further, in the color development processing bath, the constituents dissolved from the silver halide color photographic material accumulate to a high concentration. As a result, stains arise at an unexposed sections, and apparent whiteness is deteriorated.
The number of mini labs. has increased rapidly in recent years. For example, the number of the mini labs. present as of May 1985 in Japan is approximately 3,000, and at least one third thereof is said to have been built in the past one year. Thus the mini labs. became very popular. In the mini labs., only several workers are present normally. For example, besides selling cameras and films, the workers are engaged in printing service. Therefore, the workers are very busy and short-handed. In the case where the apparatus runs out of the replenishing solution when the workers are very busy, they must stop printing work and perform dissolving work for the replenishing solution. Since the concentration of the replenishing solution for color development has been increased in recent years, it takes long time for dissolving work. Therefore, in the mini labs., it is strongly desired that the dissolving work for the replenishing solution may be achieved easily and as quick as possible even though the concentration of the replenishing solution is high. Also, as mentioned above, as low replenishment of concentrated replenishing solution for color developing solution is increasingly employed in recent years, the pH value of the replenishing solution is adjusted to an increasingly high value in order to maintain the pH condition of the color development processing bath with low amount replenishment. However, it is not always possible to maintain the high pH value. Thus there is also a need for solving this problem. Further, under the aforesaid situation wherein the mini labs. became popular, it is strongly desired to develop a method of processing the silver halide color photographic material, which provides consistent photographic performance regardless of the type of the automatic developing machine. As mentioned above, as low replenishment with concentrated replenishing solution for color developing solution is increasingly employed in recent years, it is also strongly desired to minimize deterioration of whiteness of the unexposed sections even with addition of small amounts of the replenishing solution.